BRUEL & KJAER 2209 - Vibration

N
120
E
-
z
1.!)
I
0
110
N
~
OJ
~
Cii
100
>
Q)
...J
Q)
.....
::J
Cl)
Cl)
Q)
90
Q:
"'0
c
::J
0
C/)
"'0
40
Q)
+-'
ro
. ~
"'0
c
30
20
Applied SPL
- .
= Inherent Noise Measured with Microphone
= Replaced by Equivalent Capacitance
I
J Jl
II
_l_
1 ..L..I. '
I Ul 'V
/F F FF 1 /F /
'F
F
20
100
1.000
Fig.5.13. Influence of sound field
1.1
. ·· -
- -:- -
-
\:.
FF
-
-
-
M
-
F F
'F
10,000
Frequency (Hz)
-?'704-67'
but in all cases, no matter what the position of the WEIGHTING NET-
WORK
SWITCH, the sensitivity is at least 60 dB below that of the meter
with the 1 inch microphone.
5.8. VIBRATION
The effect of vibration on a typical microphone and input stage is shown
in Fig.5.14.
The constant 1 g acceleration is applied at the fixture screw
holes for
the tripod in cases a, b, c & d. In cases e and f the instrument was
firmly clamped
to the vibration platform.
60